(1) Field of the Invention
The invention relates to a method for producing a combined optical film including a plurality of optical films with their end faces opposed to one another and to an apparatus for use in the production method. The invention also relates to a combined optical film obtained by the production method. The combined optical film obtained by the production method is suitable for use in methods of producing a liquid crystal panel and a laminated optical film. The invention also relates to an image display, such as a liquid crystal display and an organic electroluminescent display, using the combined optical film.
Examples of the optical film include a polarizer, a protective film to be laminated on one or both sides of a polarizer, a polarizing plate including a polarizer and the protective film laminated on one or both sides of the polarizer, a retardation plate, an optical compensation film, and a brightness enhancement film. Any one of these optical films may be used alone for the combination optical film, or a laminate of any of these optical films may be used for the combination optical film.
The optical films to be used may each include an optical film and an easily-releasable protective film provided on the front surface of the optical film and/or a separator provided on the back surface of the optical film with a pressure-sensitive adhesive layer interposed therebetween.
(2) Description of the Related Art
Image displays such as liquid crystal displays for use in televisions, personal computers and the like use optical films such as polarizing plates. As the size of televisions and the like has grown in recent years, large-area optical films have been demanded. For the manufacture of large-area optical films, corresponding large manufacturing facilities are necessary, and a difficulty in handling for packing is associated with transportation, which requires high cost. In order to install such large manufacturing facilities, a large place is required. Thus, there has been proposed a technique in which a plurality of liquid crystal displays are arranged with their end faces butted against one another to form a large-sized liquid crystal display.
Liquid crystal displays of televisions, personal computers and the like produce a display by transmitting and blocking (absorbing) light from their back side based on the function of optical films such as polarizing plates. Thus, butting of the end faces of liquid crystal displays has a problem in which the butted portion can cause light leakage to produce a light line on the front face of liquid crystal displays. Against this problem, there is disclosed a technique that a film is attached onto polarizing plates (optical film) at the butted portion of liquid crystal displays to prevent light leakage (JP-A No. 05-88163). However, the technique of Patent Literature 1 has a problem in which the film attached to the surface of the polarizing plates can degrade the surface appearance of liquid crystal displays, although light leakage can be prevented. There is also proposed a combined optical film comprising a plurality of optical films with their opposed end faces each controlled to have a specific shape (JP-A No. 2006-163377). Such a combined optical film can prevent light leakage without degrading appearance. It has been desired to narrow the gap between the opposed end faces in such a combined optical film.